Folding square.



PATBNTED AUG. 6, 1907. S. J. MULLIN.

FOLDING SQUARE.

APPLIOTION FILED NOV. 24, 1906.

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No. 862,269. PATENTE!) AUG. '6, 1907.

l -S. J. MULLIN.

FOLDING SQUARE.

'APPLIOATIIOH FILED NOV. Z4, 1906.

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Qfvtwzooeo 5 I r` /d Emma? SAMUEL J. MULLIN, -OF SAN FRANCISCO, CALIFORNIA.

FOLDING SQUARE.

Specification of Letters Patent.

Patented Aug. 6, 1907.

Application filed November 24, 1906. Serial No. 344,995.

To all whom it may concern:

Be it known that I, SAMUEL J. MULLIN, a citizen of the United States, residing at San Francisco, county of San Francisco, and State of California., have invented certain new and useful Improvements in Folding Squares, of which the following is a specification.

My invention relates to folding squares.

The obj ect of the present invention is the provision of a folding square of simple, inexpensive, strong and durable construction provided with locking means of novel construction, whereby accuracy in securing the parts of the square at different anglesin relation to each other is obtained and a defect incident to folding squares is obviated.

Another object of the present invention is the provision of a folding square having a joint of novel form.

The invention is fully set forth hereinafter and rccited in the appended claims.

In the accompanying drawings: Figure l is a sid elevation, dotted lines representing one leg of the square disposed at an angle to the other leg thereof; Fig. 2, a view showing the square completely folded; Fig. 3, an edge view looking in the direction of the arrows of Fig. l; Fig. 4, a view similar to Fig. l, with parts broken away; and Fig. 5 an enlarged detail of the locking catch and notched part of the leg of the square.

The legs of the square are shown at l and 2, the former having a bifurcated head 3 which receives between its parts the thinned head 4 of the leg 2. The head 3 is provided with the interior curved wall 5, and the ends of said head are rounded at 6. The thinned head 4 has a rounded end 7 corresponding to the curved wall 5, and it also has shoulders 8 provided with rounded parts 9 corresponding to the rounded parts G, while this thinned head also has a straight part l0 forming an abrupt termination of the rounded surface 7 and adapted to abut against a corresponding abrupt face or shoulder ll. The heads of the two legs are pivoted together by a screw-bolt l2 whose head is sunk in one part of the bifurcated head 3 and the blank part of its shank passed through said part of the head and through the thinned head 4, and the screw-threaded part of the said screw is screwed into the remaining part of the head 3. The parts of the head 3 are more or less springy and by tightening the said screw l2, these parts of said head 3 may be clamped firmly to the thinned head 4 and thereby the legs of the square may be secured at any desired angle, but it is desirable to provide means for positively locking the legs at certain angles which are very commonly laid off by the artisan using squares and I, therefore, provide the rounded part 7 of the thinned head 4 with tapered or wedge-shaped notches I3, of which three are preferably employed.

In the guide-pocket 14 in the head 3 there is mounted a slidable latch l5 which is pressed by a spring I6 and may be retracted by a thumb-piece 17 whose shank is threaded into the latch l5 and whose head slides in an elliptical sunken portion or recess 18 in the head 3. This latch l5 has a tapered tip 19 which is of less depth than the depth of the notches 13 and, in consequence, when received in said notches, the end of the latch does not strike the bottom of the notches.

This construction has decided advantages over latches heretofore employed for locking the legs of a folding square because there is a wedging action and the spring tends to force the tapered end of the latch deeper in the notch and hence great rigidity in the locking action is obtained and all compensation for wear is had. If the latch becomes worn after a long period of use, the shape of the end thereof and of the notches provides just as firm and accurate av locking feed or action as obtained at all times previously. When the latch is pressed back by applying the linger to the thumb-piece 17, the legs of the square can be opened and brought to any desired angle. For the ordinary angles, the locking device may be used, but if any intermediate angle is desired,`this can be obtained by tightening the pivot screw l2.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:-

1. In a folding square, the combination with legs ha'ving a pivotal connection with each other, one of said legs having a tapered notch or recess in its end, and a latch carried by the other leg which has a tapered tip adapted to be received in the notch and to engage both walls thereof, said tapered tip being of less length than the depth of the tapered notch, whereby a wedging action is obtained.

2. In a folding square, the combination with legs having a pivotal connection with each other, one of said legs having a tapered notch or recess in its end, and a springactuated latch carried by the other leg which has a tapered tip adapted to be received in the notch and to engage both walls thereof, said tapered tip being of less length than the depth of the tapered notch, whereby a wedgingl action is obtained.

In testimony whereof, I hereunto afx my signature in presence of two witnesses.

SAMUEL J. MULLIN.

Witnesses:

G. W. ARCHIBALD, F. H. LAWTON. 

